1. Field of the Invention
The present invention relates to dental implements. More specifically, it relates to a retaining aid for the metal contour band placed around a tooth when a proximalocclusal cavity in the tooth is to be filled. The device allows for improved contact between the contour band and the adjacent tooth which assures that the tooth worked upon will be in contact with the adjacent tooth after the cavity is filled. The retaining aid of the present invention has a generally arcuate and resilient main body with a pair of downward and inwardly depending tines or legs on each end. The distal ends of the legs can be slightly bulbous and may be coated or dipped in a substance imparting a high friction coefficient thereto. Optionally, the tips could be flattened or adapted to receive a disposable cover made of a rubber or like substance or simply have a bulbous tip in metal.
2. Description of the Prior Art
When the decayed portion of a tooth is located near the interproximal area between adjacent teeth, the most common way to guarantee that the filling properly conforms to the original shape of the tooth is to set a tooth reconstruction element, such as a thin band usually made of stainless steel or the like, about the tooth and secure it tightly thereto such that the band forms an outer shell or matrix that allows the filling material to harden in the correct shape. The present invention is an apparatus that aides the practitioner in retaining the matrix band in proper proximity to the tooth being worked upon. The resilience of the arcuate main body provides for the two depending legs to be urged inwardly toward one another to ensure a conforming matrix fit and also holds the retaining apparatus in place.
The depending legs can be of varying lengths to allow a plurality of the devices to be superimposed, one above the other, to allow for complex restoration processes or allows more than one tooth to be worked on at a time. A material providing a high frictional coefficient that can be coated onto the bulbous tips of the legs helps to prevent the apparatus from slipping and allows the device to be used with a variety of differently shaped teeth. A search at the U.S. Patent and Trademark Office uncovered a number of patents that relate to this invention, and they are discussed hereinafter.
First is U.S. Pat. No. 4,824,365 issued on Apr. 25, 1989 to Hans von Weissenfluh. This discloses a matrix in a flexible strip with an integral tightener. The flexible strip has two terminal extensions that are fastened to tabs extending from an annular tightener made of permanently deformable material. Thus, when the tightener is compressed, the flexible loop around the tooth is likewise tightened. This is dissimilar from the present invention in that there is no teaching of a separate flexible retainer with the depending legs.
In U.S. Pat. No. 4,303,389 issued on Dec. 1, 1981 to Angelo Salsarulo there is disclosed an instrument for the application of fillings. Though this discloses a matrix retainer that has an open end, there are no depending legs for engagement with the matrix.
U.S. Pat. No. 2,790,238 issued on Apr. 30, 1957 to Frank M. Trangmar discloses a dental matrix having a thicker, deformable portion to facilitate tightening the unit about the tooth to be worked on. Clearly, this is dissimilar from the present invention in that there is no resilient body with depending legs to aid in guaranteeing the interproximal contact between teeth after the filling has hardened.
U.S. Pat. No. 2,567,101 issued on Sep. 4, 1951 to Victor H. Carpenter discloses a matrix band for use in filling dental cavities. This band includes a spherical concavity located at a point thereon to allow for a rounded filling after hardening, thereby maintaining the proximal contact between the teeth. This is unlike the present invention in that no matrix retaining means is disclosed.
U.S. Pat. No. 3,548,500 issued on Dec. 22, 1970 to Theodore J. Cohen discloses a method of taking dental impressions. This is clearly dissimilar from the instant invention in that no separate retaining means for the matrix holder is taught.
U.S. Pat. No. 677,268 issued on Jun. 25, 1901 to Roscoe 0. Power discloses a dental instrument. This invention includes a horseshoe-shaped spring clamp to hold the matrix retainer in place, however there is no teaching of the depending legs and bulbous gripping tips of the present invention.
Lastly, U.S. Pat. No. 644,705 issued on Mar. 6, 1900 to George Evans discloses an impression band for dentistry. Projections are formed or soldered onto the side of the band ring and when the impression hardens, the ring is thus removed with the impression material. Contrast this to the present invention wherein depending legs apply pressure to the interproximal spaces bound by the matrix retainers.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.